Silicon Sea

The more than complete archive

I have collected all the silicon sea problems I could find, and created an archive through leg 91. I have included the questions to leg 91, but not the answers, as I do not have the official answers from Dan Hogan, and I have not worked the problem through for myself.

Silicon Sea problems archive
The original set of Silicon Sea problems, answers, and charts can be found on The Navigation-L Page

Track of the Silicon Sea

The Voyage of the Silicon Sea contains about 80 legs, each one with 5 to 7 problems. Creating these problems was an enormous amount of work for Dan Hogan and the Silicon Sea working group. They created some intentional errors. They created some unintentional ones, too.[1] So have fun! Find out where Dan Hogan and the working group have made intentional errors. Would you make this same kind of error while on passage? If you were short on sleep because of weather or the risk of piracy? Can you find any unintentional errors?

Microsoft's Virtual Earth[2] -- supplies good, quick way to check DR work. Work your DR plots and Fixes on a plotting sheet and/or on one of the Silicon Sea chartlets. Record your latitudes and longitudes. Put them into Virtual Earth (see below) and see if they make sense.

Legs 10 through 16 -- Mallorca to Malta. You can see the DR track seems to be over land from leg 12 to leg 13
Legs 17 through 23 -- Malta to Port Said.
Legs 24 through 27 -- Port Said to Djibouti
Leg 28 -- Planning the passage from Djibouti to Sydney
Leg 29-34 -- Djibouti to Malé

All NAVLIST readers are welcome to use, modify, and improve (PLEASE!) my code in order to facilitate planning and discussions on NAVLIST. If you can correct any errors in my work or can improve my presentation here, please contact me via the NavList.

If you have any questions about how to move around, zoom in and out, etc, you can get the answers at local.live.com. I haven't figured out how to use all the nice features. And I probably won't.

How to Plot Your Own

The Time-Tested Way

This is a skill we should all have and practice. Even if you have electronic charts, you need to maintain a "real" one as a safety backup. Fortunately, the skills you need are easy to learn, and there are many good books to instruct you. Just do it. Whenever you can get hold of a chart. Even a lousy one. All charts have problems, and it is worth thinking about how to plan your trip, knowing that the chart has errors you are not yet aware of. When working the Silicon Sea problems, you can use the Silicon Sea chartlets.

Using local.live.com to create a collection of pushpins

Unfortunately, the developers have not yet created a way for you to create a collection of pushpins from a latitude/longitude. That's really unfortunate, because this WOULD BE the easiest way to do it. CAUTION: I have tested centering the map on a given lat/long (example: http://local.live.com/default.aspx?cp=35.905~14.53) and telling the map to create a pushpin at its center, but the pushpin doesn't always go where it is "supposed" to go.

Write your own HTML file (or copy mine)

I worked out an ALMOST simple way to throw up a bunch of points quickly. You won't have to write a lot of code. Just borrow mine. You can create maps on your own computer for your own use. If you want to share them, you should put them up on a website somewhere. You are welcome to use and/or improve (please!) on what I have done. If you make an improvement, please share it with me.

Get file that actually builds the displays -- displaybuilder.js
Create a file to tell it what to display. You can start by taking a copy of this sample display
Put the two of them in the same directory. Read the instructions in the sample display file. Create one of your own. You don't need to look at the .js file.

1. Recently, Dan Hogan emailed me the following comments about the problems

The Silicon Sea problems were originally intended to create discussion among the Navigation-L list.
"SOME" errors were intentional others accidental
...
Plotting the Silicon Sea Legs was done with posplot.exe
Calculations were done with Navig and checking with a pair of HP 32SII using the USPS arc sine formula.
Destination positions were selected from Pilot Charts of the area (old and current), an World Atlas, or Ocean Passages For The World.
There was a "Working Group" of list members that double checked and helped develop the problems before they were posted.
The members changed over time.

2. Microsoft's Virtual Earth is still under development, but already makes it relatively easy to plot some points onto a world map derived from satellite photographs and show them to millions of people around the world. Virtual Earth is not a substitute for an actual marine navigation chart. It does not show all the rocks, reefs, wrecks, and other dangers a real chart would show. It does not label landmarks, lights or other navigational aids. And it will not help you to build skill at plotting your position on a real paper chart. But it does make it easy to double check your work.